The use of mobile communications devices has become commonplace in today's society. As consumers of mobile communications services become more sophisticated, it becomes more important for service providers to offer more and better services in order to fully meet their subscribers' needs. Such value-added services have become an integral part of the consumer's expectations regarding their mobile communications service.
Many of these value-added services relate to the provision of Intelligent Network (IN) services such as video or music download services, automated call forwarding services, ring-back tone services, prepaid services and the like. In the Global System for Mobile Communications (GSM), the Customized Application of Mobile Enhanced Logic (CAMEL) standard has been developed to aid GSM operators to offer operator-specific services to their subscribers, even if a subscriber is roaming outside their home network. These services can include call processing functions such as caller ID and call screening, call forwarding, call rerouting; charging functions such as location-based charging or personal discounts; and provision of tones and announcements to provide information regarding a call to a subscriber's mobile telephone.
CAMEL protocol is defined in a set of standards established by the ETSI (European Telecommunication Standardization Institute) and later upgraded as part of 3GPP (Third Generation Partnership Project) initiative. These standards can be found on the World Wide Web at http://webapp.etsi.org/key/queryform.asp. Additional information regarding CAMEL networks can be found in many publications. The most comprehensive work on CAMEL including the latest standardization enhancements can be found in the book by Rogier Noldus entitled, CAMEL, Intelligent Network for the GSM, GPRS and UMTS Networks, published by John, Wiley & Sons Limited (2006). Other publications that describe the architecture and operation of a mobile network using CAMEL functionality include “Customised Applications for Mobile Enhanced Logic (CAMEL),” by Paulius Meskauskas for the Research Seminar on Nomadic Computing for the Department of Computer Science at the University of Helsinki; the CAMEL tutorial by Zahid Ghadialy entitled “CAMEL: An Introduction,” (Jul. 25, 2004), available on the World Wide Web at http://www.3g4g.co.uk/Tutorial/ZG/zg_camel.html; and “An Introduction to GSM Enhancements for Operator Specific Services (CAMEL)” (1996) by David G. Smith, published by the IEEE, Savoy Place, London. Information regarding CAMEL triggers and trigger detection points may also be found in U.S. Patent documents such as, for example, U.S. Pat. No. 7,050,811 to Grech et al. and U.S. Patent Application Publication No. 2003/0095566 to Bunting et al.
Information regarding CAMEL networks may also be found in U.S. patent application Ser. No. 11/754,808 entitled “Optimized Camel Triggering for Prepaid Calling,” filed May 29, 2007; U.S. patent application Ser. No. 11/765,655 entitled “Conditional Call Treatment For Prepaid Calls,” filed Jun. 20, 2007; and U.S. patent application Ser. No. 11/781,459 filed Jul. 23, 2007; U.S. patent application Ser. No. 11/846,259 entitled “Peak Off-Peak Rating for Prepaid Terminating Calls,” filed Aug. 28, 2007; U.S. patent application Ser. No. 11/846,277 entitled “Decisionmaking for Dynamic Local Time Updates in a Prepaid Terminating Call,” filed Aug. 28, 2007; and U.S. patent application Ser. No. 11/846,299 entitled “Determining Capability to Provide Dynamic Local Time Updates in a Prepaid Terminating Call,” filed Aug. 28, 2007, each of which shares at least one common inventor with the present application and each of which is hereby expressly incorporated by reference herein in its entirety.
Processing of a call in a CAMEL network can be accomplished by means of signaling between one or more of a subscriber's Home Location Register (HLR), a visiting Location Register (VLR) associated with the Mobile Switching Center (MSC) where the mobile subscriber is currently located, a Gateway Mobile Switching Center (GMSC), and a Service Control Point (SCP). CAMEL works to enable the provision of enhanced mobile services by providing CAMEL Application Part (CAP) messages, for communication between an SCP and an MSC handling an outgoing call or a GMSC handling an incoming call.
CAMEL also provides a Basic Call State Model (BCSM), which describes the different phases of call processing in the MSC. An Originating Basic Call State Model (O-BCSM) describes the call processing for a mobile-originated call, i.e., a call where the calling party is originating a call from her mobile device. Similarly, a Terminating Basic Call State Model (T-BCSM) describes the call processing to route a terminating call to the mobile subscriber as a recipient of an incoming call. Both the O-BCSM and T-BCSM contain various points in the call processing between the MSC and the SCP. Each state is preceded by a transition step, or Detection Point (DP) where the call is handed over to the SCP for a determination whether the call can proceed to the next state.
Control of a call in a CAMEL network can be managed by the SCP and the MSC or GMSC through the use of DPs (both TDPs and EDPs) and CAP operations. A CAP operation message from the SCP to the MSC can contain instructions regarding the handling of the call at that point or from that point onward. For example, Operation: RequestReportBCSMEvent is used to arm future DPs which contain instructions for future processing. CAP operations also are used to send messages between the MSC and the SCP regarding a status of the call. For example, an operation such as Operation: EventReportBCSMEvent can be used by the MSC to report to the SCP that the call has been answered.
One of the services provided in a CAMEL network is prepaid mobile service, both for mobile originators and mobile recipients of calls in the mobile system. Prepaid mobile service is a popular option for many users. It can enable a user to enjoy the benefits of mobile communications without having to enter into a long-term contract. Prepaid mobile service also can be useful to facilitate management of mobile service. For example, prepaid service can be used to as a parental control tool to manage a child's use of mobile telecommunications services. Prepaid service also can be used by businesses as a management tool to monitor and control corporate use of mobile resources.
Charging for a prepaid call in a CAMEL network is handled by the SCP based in part on CAP messages from the MSC. If CAP messaging between the MSC and the SCP fails, but the call continues due to the subscriber's default call handling instructions, the SCP cannot easily charge the subscriber's prepaid account for the portion of the call occurring after contact with the MSC is lost.